add fix for MacOSX returning different IP address from ntop..

import socket
socket.inet_ntop(socket.AF_INET6, socket.inet_pton(socket.AF_INET6, '::111'))

on other OS's like FreeBSD, return ::111 properly, but on MacOSX, returns
::0.0.1.17.

tests/test_functional.py

@@ -214,7 +214,8 @@ async def test_socks5_atype_ipv6(loop):
 
         transport, protocol = await aiosocks.create_connection(
             None, addr, auth, dst, loop=loop)
-        assert protocol.proxy_sockname == ('::111', 1111)
+        assert protocol.proxy_sockname == ('::111', 1111) or \
+            protocol.proxy_sockname == ('::0.0.1.17', 1111)
 
         transport.close()